In the treatment of waste water, particularly in septic tanks, it is common to install filters to remove particulates being discharged from the tank which are generally undigested solids so that the discharging effluent is a relatively colorless and harmless liquid. There have been a number of filter units designed over the years for the removal of these undigested solids from the waste water prior to discharge from a septic tank or the like. For example, U.S. Pat. Nos. 2,900,084; 3,332,552; and, 4,710,295 to Robert Zabel teach a waste water treatment filtration system which includes a plurality of disc-dam units disposed in a stack, vertically spaced, in a super-imposed relationship such that the bottom of each overlying disc-dam unit cooperates with the upper edges of each underlying unit to form a horizontally elongated vertically narrow outlet slots. The stack of disc-dam units are mounted in a cylindrical housing with several slots located above and several slots located below the liquid operating level in a waste water tank. In operation, the digested waste water is received through a bottom opening of the housing and the discharging clarified effluent flows through a sidewall outlet which is in flow communication with an outlet from the waste water tank. However, it has been found that septic tanks or waste water treatment tanks come in different sizes and capacities and also the outlet discharge from the waste water tank is not of a standard size. Thus, for residential and commercial applications it is difficult to provide a filter housing unit of varying filtration capacities and with discharge outlets adaptable to mate with the various sizes of outlet discharge pipes or conduits from the waste water treatment tank.